Blake Hayes was the much-older ex-husband of Dr. Taylor Hayes. Divorced from Taylor before he ever came to town, Blake had not been able to let go of his ex-wife, and also suffered from a medical condition that made him violent. Unfortunately, the only person that Taylor had any interest in was Ridge Forrester. After encountering Margo at the Taxi Bar one night, he became enthralled with her and by what he thought the Forrester employee could do to help him break up Ridge and Taylor. He rented the apartment across the street from Taylor and watched her. He even joined forces with Brooke Logan, who also wanted to split up Ridge and Taylor.

Blake swore to Taylor that he had successfully sought treatment for his violent tendencies, which had been the reason for their divorce. The two made love after going out to dinner one night, but the moment was ruined for Blake when Ridge answered the phone at Taylor's apartment. After learning that Stephanie (who had been helping him break up Taylor and Ridge) had secretly taped Ridge and Brooke making love on the laboratory floor, Blake stole the tape to give to Taylor. She initially blamed him until Stephanie confessed to recording it.

The tape incident hurt Blake rather than helped where Taylor was concerned. Blake finally acknowledged how much Taylor loved Ridge, and tried to make a go of it with Margo, who had been pretending they were having an affair to get her husband's interest. When Blake and Margo shared a kiss and Bill found them, Bill verbally attacked Margo and Blake attacked Bill. Despite leaping to Margo's defense, the incident helped both Blake and Margo realize that they weren't over their exes. When Ridge was attacked and hospitalized a short time later, both Margo and Taylor suspected Blake.

Blake accepted that he had no chance with either Margo or Taylor and decided to leave town. During his goodbye with Margo, she mentioned that Caroline Spencer had a twin sister, Karen, who was kidnapped years ago. Blake filed this little tidbit away, but it was by accident that he ended up in Starlight, Texas, where he soon met Bonnie Roberts and her daughter, 'Faith', a waitress who bore an alarming resemblance to Caroline. Blake immediately befriended Faith, seeing her as a way to not only win back Taylor, but give Bill Spencer a wake-up call.

With Faith in tow, Blake returned to Los Angeles, determined to make Ridge believe she was Caroline in order to get Taylor for himself. Although Faith had initially been interested in Blake, it wasn't long before she turned her attentions to Ridge, and called herself Karen in an attempt to take back her old life. Blake finally tried to confine Karen to her room so that he could get to Taylor, but after Thorne and Bill rescued Karen and Taylor became her new best friend, Blake gave up and left Los Angeles for Texas.